Electronic devices, such as computers and their various internal components (e.g., microprocessors, memory boards, disk drives, etc.) require power. The typical source is a 110-120 volt or 220-240 volt alternating current (AC) feed, supplied by a utility company. In many devices, the AC current is converted into direct current (DC) for use by internal components.
In instances where nonstop operation is critical, electrical devices may be fed by multiple power sources and/or provisioned with multiple power supplies to guard against inadvertent power loss. Servers and other enterprise computers are an example.
One way to supply redundant power is through multiple (usually, two) feeds from separate AC sources to the device requiring power. In this way, loss of one AC source does not force shutdown of the device. However, to ensure continuous power, the device must be equipped to switch between the AC sources quickly enough to avoid even temporary disruption, as well as to avoid spikes or other transients. Such switching circuitry can be complicated, requiring multiple relays, as well as processing logic, to detect power source failures and to effect switching. The switching and/or logic circuitry can also be expensive in monetary cost and/or in its consumption of space (e.g., within the powered device).
One object of the present invention is to provide improved power supply methods and systems.
A further object is to provide power supply methods and systems that can be implemented at low cost.
A still further object of the invention is to provide scalable power supply methods and systems.